1. Field of the Invention
The present invention is directed generally to managing use of digital content. In particular, this invention relates to establishing usage rights for controlling such use before the content is created, and distributing licenses to allow use of the content when the content is created.
2. Description of Related Art
One of the most important issues impeding the widespread distribution of digital works via electronic means, and the Internet in particular, is the current lack of protection of intellectual property rights of content owners during the distribution and the usage of the digital content. Efforts to resolve these issues have been termed “intellectual Property Rights Management” (“IPRM”), “Digital Property Rights Management” (“DPRM”), “Intellectual Property Management” (“IPM”), “Rights Management” (“RM”), and “Electronic Copyright Management” (“ECM”), collectively referred to as “Digital Rights Management” (“DRM”) herein.
Due to the expansion of the Internet in the recent years, and the issues relating to privacy, authentication, authorization, accounting, payment and financial clearing, rights specification, rights verification, rights enforcement, document protection, and collection of licensing fees DRM has become even more important. Because the Internet is such a widely used network whereby many computer users communicate and trade ideas and information, the freedom at which electronically published works are reproduced and distributed is widespread and commonplace.
Two basic types DRM of schemes have been employed to attempt to solve the document protection problem: secure containers and trusted systems. A “secure container” (or simply an encrypted document) offers a way to keep document contents encrypted until a set of authorization conditions are met and some copyright terms are honored (e.g., payment for use). After the various conditions and terms are verified with the document provider, the document is released to the user in clear form. Commercial products such as IBM's CRYPTOLOPES™ and InterTrust's DIGIBOXES™ fall into this category. Clearly, the secure container approach provides a solution to protecting the document during delivery over insecure channels, but does not provide any mechanism to prevent legitimate users from obtaining the clear document and then using and redistributing it in violation of content owners' intellectual property.
Cryptographic mechanisms are typically used to encrypt (or “encipher”) documents that are then distributed and stored publicly, and ultimately privately deciphered by authorized users. This provides a basic form of protection during document delivery from a document distributor to an intended user over a public network, as well as during document storage on an insecure medium.
In the “trusted system” approach, the entire system is responsible for preventing unauthorized use and distribution of the document. Building a trusted system usually entails introducing new hardware such as a secure processor, secure storage and secure rendering devices. This also requires that all software applications that run on trusted systems be certified to be trusted. While building tamper-proof trusted systems is a real challenge to existing technologies, current market trends suggest that open and untrusted systems such as PC and workstations using browsers to access the Web, will be the dominant systems used to access digital works. In this sense, existing computing environments such as PCs and workstations equipped with popular operating systems (e.g., Windows™, Linux™, and UNIX) and rendering applications such as browsers are not trusted systems and cannot be made trusted without significantly altering their architectures. Of course, alteration of the architecture defeats a primary purpose of the Web, i.e. flexibility and compatibility.
U.S. Pat. Nos. 5,530,235, 5,634,012, 5,715,403, 5,638,443, and 5,629,980 introduced many basic concepts of DRM. The disclosures of all of these patents are hereby incorporated herein by reference in their entirety. For example, U.S. Pat. No. 5,634,012 discloses a system for controlling the distribution of digital works. Each rendering device has a repository associated therewith. A predetermined set of usage transaction steps define a protocol used by the repositories for carrying out usage rights associated with the content. Usage rights are encapsulated with the content or otherwise associated with the digital content to travel with the content. The usage rights can permit various types of use such as, viewing only, use once, distribution, and the like. Rights can be granted based on payment or other conditions.
In conventional DRM techniques, a content owner, or other authorized party, specifies the rights after the content has been created and protects, e.g. encrypts, the content at the same time. A private key is used to encrypt the content, and a label is generated which specifies the usage rights. The rights label and the protected content are then associated and stored. A license to the content can later be generated for a user to permit the user to use or access the content. The license can include a private key which has been encrypted using a public key in known manner.
To access the content, the private key can be used to decrypt the encrypted public key, allowing the user to decrypt the content. This technique works well if the content is available at the time of the rights specification. However, this technique breaks-down if one wants to specify rights for content and issue a license for the content before the content is available. For example, a distributor of streaming video to a live future event, or of photographs to a future event, may want to begin selling licenses to the content prior to the event. Conventional DRM systems fall short of presenting processes for improving the security for works that are not yet in existence.